Process for the preparation of paper containers



March 27, 1962 H. MAJER 3,02

PROCESS FOR THE PREPARATION OF PAPER CONTAINERS Filed June 21, 1961 2 Sheets-Sheet 1 March 27, 1962 This invention relates to improvements in the manufacture of paper containers or cups and has particular relation to a novel and improved method for gluing together the bottom provided with an edge or flange, in conical or cylindrical containers which consist of carton provided with a protective layer, the lower rim of the conical or cylindrical wall of such containers being turned around said edge or flange of the bottom.

The protective layer of the carton may consist e.g. of a suitable plastic material, such as polyvinylchloride, which is applied to the paper sheet e.g. by coating or other suitable method in conventional manner and the parts for the cylindrical or conical surface and the bottom are cut out from such carton.

In using such carton it has been found particularly difficult to produce a water-tight connection at the joints of the container, because the gluing together of layers or their hot-sealing by devices hitherto used in the processing of cartons having no protective layer is extremely diflicult and may result in leaking spots. The main reason for this consists in that a carton covered by a protective layer swells to a lesser extent when becoming wet so that any defect in the glue may cause leakage immediately. Gluing or cementing of the surface layer to paper is also more diificult than gluing carton to carton and requires longer gluing periods.

In order to avoid this difliculty in gluing the jacket, in providing the carton with a protective layer, on those parts of the carton which form the overlapping, the layer can be omitted. This is particularly simple in twofold wound containers, in which the jacket is twice wound. In this case, only one-half of the carton sheet is provided with the surface layer and winding is carried out in such manner that the coated surface is located in the interior of the container and the uncoated surface on the outside, so that in the overlapping winding uncoated carton lies on uncoated carton and the surface layer covers the interior space only. A similar procedure was suggested for container with single winding, but in this case omission of the surface layer on the web of paper in simple manner is possible only if the place to be omitted extends parallel to the edge of the carton web.

The present invention is not concerned with the joint of the jacket surface and it relates to the joint between the container jacket and the bottom inserted therein.

According to the present invention the container bottom is connected with the jacket edge to be folded over the edge or flange of the bottom in the following manner.

The jacket to be wound is made, in a manner known per se, of a carton web, only one-half of which is provided with a surface layer or coating. The jacket to be wound is cut out from this web in such manner that after bending the lower edge of the jacket over the edge or flange of the bottom part, which is coated only on one side, only the uncoated outer surface of the jacket edge comes in contact with the uncoated surface of the bottom edge or flange, so that the bottom and the jacket edge have a common contact surface which extends over the entire periphery, in which carton lies on carton and which can be used for gluing.

The appended drawings illustrate by way of example 3,026,779 Patented Mar. 27, 1962 and without limitation the process of this invention. In the drawings;

FIGURE 1 is the cross-sectional view of a conical container of the type described in more detail hereinafter, the bottom portion being shown also on an enlarged scale;

FIG. 1A is an enlargement of the bottom and the cup shown in FIG. 1 in cross-sectional view.

FIGURE 2 is the perspective view of a container jacket according to the invention;

FIGURE 3 illustrates a carton sheet and the design for cutting out the carton for the jacket of the container;

FIGURES 4 and 5 diagrammatically illustrate the assembling of a carton jacket with the bottom of a container.

It will be understood from FIG. 1, in which by way of example the cross-section of a conical container or cup is shown, that in the conventional process the lower edge of the container jacket is put round the bottom by a simple folding step. Before this is done, the edge of the jacket, or the rim of the bottom is provided with glue which is located between the outer surface of the bottom and the jacket wall at 1, or between the inner surface of the bottom and the jacket wall at 2, or at 1 and 2. If, however, carton provided with a protective layer is used, then such layer will be present on the inner jacket surface, as well as on the bottom surface directed toward the interior surface of the jacket wall, as shown in FIG. 4. The layer is here indicated by a curled line 3. In this example, the jacket wall is twofold wound, as described above. The surface layer is on the inner side. It can be seen that at the joint either one surface layer contacts the other as in section 4 to 5, or surface layer and carton are in contact, as in section 6 to 7, whereby gluing and sealing becomes difficult.

According to the present invention it has become possible to design the twofold wound jacket surfaces in such manner that at the joint between jacket and bottom, at least partially, carton lies on carton, so that gluing in simple manner is possible.

According to FIGURE 5 this advantage is attained in such manner that the surface coated part of the twofold Wound jacket extends only up to the edge 10 and the inner side provided with a surface layer, is not turned around so that in section 8 to 9 carton lies on carton. In order to carry out such a sealing of the bottom, the design of the material to be cut out and wound twofold has to be selected in the manner shown in FIG. 3 which represents the example of a jacket segment for a conical container. In this FIGURE 3 one-half 11 of the carton sheet having the edges 13, 13, is provided with a surface layer, while the other half 12 of the carton sheet has no surface layer. The exactly twofold winding of the jacket of the truncated cone, which must be first formed in the manufacture of the container, yields a geometrical figure indicated by the points 14, 15, 16, 17. The surface 17, 18, 19, 20 is now cut-off during punching out this segment, so that upon winding of the jacket surface, the upper part of the jacket shown in FIG. 2, is formed by the projecting flap 16, 21, 19, 20 only. The dotted line 1921 in FIGURE 3 indicates the line, up to which the two segment parts overlap each other when the winding is completed. Such segment forms after winding a jacket according to FIG. 2, in which the points marked in the segment can be found. The line 20, 19, 22 represents about the middle line of the segment which approximately corresponds to the generatrix of a cone. If the upper inner edge of the jacket is followed clockwise from point 19, the end of the line will be at 18. If the edge is followed from 19 in the opposite direction, it will lead over the higher corner 20 to the end 16 of the upper .such manner that carton lies on carton.

outer edge. The uncoated edge portion 16, 21, 19, 20 of the jacket is laid over after the insertion of the bottom and will then contact the inner edge of the bottom in Prior to said laying over of said jacket portion glue is applied to the uncoated edge portion in the hitherto customary manner by means of the available conventional devices.

In FIG. 5 the jacket portion 23 represents the segment portion shown in FIG. 2 between points 16, 20, 19, 21. Between points 8 and 9 in FIG. 2on1y glued carton lies on carton so that in this manner gluing can be carried out simply and with hitherto available devices.

Cylindrical containers can be prepared substantially in the same manner as described above.

What is claimed is:

In the manufacture of conical and cylindrical paperboard or carton containers provided only on the inner surface with a protective coating layer, having a twofold wound jacket and a bottom member provided only on one of its surfaces with a protective coating layer and 0 having an edge or flange to be connected with said jacket, in combination the steps of cutting out from carton a circular-segment-like portion having a design adapted to be wound twofold to form the jacket of the container, a first half of said cut-out portion being provided with a protective coating layer to form the interior surface of the container and said first half having a strip cut-off from its circular periphery on the bottom side of the jacket to be formed; the second half of said cut-out portion being uncoated and having on its circular periphery of said bottom side of the jacket to be formed, an uncoated strip adapted to be folded over the flange of the bottom member; forming the jacket by twofold winding of said cut-out carton portion and assembling the jacket with the bottom member, having its coated surface on the inside of the container and folding said uncoated strip over the flange of the bottom member, so that uncoated surface of said flange lies against said uncoated folded strip.

No references cited. 

